Cancer of the exocrine pancreas in humans usually arises from ductal cells. The purpose of the proposed research is to develop an animal model for the study in vitro of the early interactions between potential carcinogens and ductal tissue of the pancreas. The first part of this project will be an evaluation of various methods for preparing relatively pure populations of pancreatic tissue. This will include a more detailed biochemical and physiological characterization of this tissue than has been thus far attempted. Secondly, methods for the in vitro culture of this tissue will be investigated, beginning with methods which are known to be effective with the embryonic pancreas. Thirdly, effects in vitro of potential carcinogens on ductal tissue and on the embryonic pancreas will be determined from biochemical, physiological, and cytological points of view, in order to characterize better the early events which eventually lead to the development of a malignant tumor.